Add a Shop menu that lists the store's collections

The header now carries a "Shop" dropdown that fetches the collection list
the first time it's opened and links each entry to its collection page.

Fetching is deferred so the request only happens on open: useCollections
loads on mount, which would put a collections query on every page. The new
useCollectionsOnDemand holds off until load() runs, keeps the result for
later opens, and clears its guard on failure so a retry can go through.

Rendered in the desktop nav as a floating panel and in the mobile menu as
an inline section, following the hand-rolled pattern in account-menu.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01D1vsTA4MX6qFd7nqSAKtdV

components/shopify/header.tsx

@@ -6,6 +6,7 @@ import { useCartStore } from '@/hooks/use-shopify-cart';
 import CartDrawer from '@/components/shopify/cart-drawer';
 import SearchDialog from '@/components/shopify/search-dialog';
 import AccountMenu from '@/components/shopify/account-menu';
+import ShopMenu from '@/components/shopify/shop-menu';
 import { RiShoppingBagLine, RiCloseLine, RiMenu3Line } from '@remixicon/react';
 import { Button } from '@/components/ui/button';
 import Logo from '@/components/logo';
@@ -88,6 +89,7 @@ const Header: React.FC<HeaderProps> = ({
 
           {/* Desktop Navigation */}
           <div className="hidden md:flex items-center gap-x-8 text-sm">
+            <ShopMenu />
             {links.map((link, index) => (
               <Link
                 key={index}
@@ -127,6 +129,7 @@ const Header: React.FC<HeaderProps> = ({
       {menuOpen && (
         <div className="md:hidden bg-background">
           <div className="max-w-screen-2xl mx-auto px-8 pb-6 flex flex-col gap-y-4 text-sm">
+            <ShopMenu mobile onNavigate={() => setMenuOpen(false)} />
             {links.map((link, index) => (
               <Link
                 key={index}

components/shopify/shop-menu.tsx

@@ -0,0 +1,152 @@
+'use client';
+
+import React, { useEffect, useState } from 'react';
+import Link from 'next/link';
+import { RiArrowDownSLine } from '@remixicon/react';
+import { useCollectionsOnDemand } from '@/hooks/use-shopify-collections';
+import { cn } from '@/lib/utils';
+
+interface ShopMenuProps {
+  label?: string;
+  /** Renders inline inside the mobile menu instead of as a floating panel. */
+  mobile?: boolean;
+  /** Fires after a collection is picked, so the mobile menu can close itself. */
+  onNavigate?: () => void;
+}
+
+const ShopMenu: React.FC<ShopMenuProps> = ({
+  label = 'Shop',
+  mobile = false,
+  onNavigate,
+}) => {
+  const [open, setOpen] = useState(false);
+  const { collections, loading, error, load } = useCollectionsOnDemand();
+
+  // The collection list is only worth fetching once someone opens the menu.
+  const toggle = () => {
+    const next = !open;
+    setOpen(next);
+    if (next) load();
+  };
+
+  const close = () => {
+    setOpen(false);
+    onNavigate?.();
+  };
+
+  useEffect(() => {
+    if (!open) return;
+
+    const handleKeyDown = (event: KeyboardEvent) => {
+      if (event.key === 'Escape') setOpen(false);
+    };
+
+    window.addEventListener('keydown', handleKeyDown);
+    return () => window.removeEventListener('keydown', handleKeyDown);
+  }, [open]);
+
+  const itemClasses = cn(
+    'block text-sm text-foreground hover:bg-accent transition-colors',
+    mobile ? 'px-3 py-2' : 'px-4 py-2'
+  );
+
+  const body = (
+    <>
+      {loading &&
+        Array.from({ length: 5 }).map((_, index) => (
+          <div key={index} className={cn(itemClasses, 'py-2.5')}>
+            <div className="h-3 w-2/3 animate-pulse bg-muted" />
+          </div>
+        ))}
+
+      {error && (
+        <div className={cn(itemClasses, 'hover:bg-transparent')}>
+          <p className="text-muted-foreground">{error}</p>
+          <button
+            onClick={load}
+            className="mt-1 underline underline-offset-2 hover:text-muted-foreground"
+          >
+            Try again
+          </button>
+        </div>
+      )}
+
+      {!loading && !error && collections.length === 0 && (
+        <p className={cn(itemClasses, 'text-muted-foreground hover:bg-transparent')}>
+          No collections yet.
+        </p>
+      )}
+
+      {collections.map((collection) => (
+        <Link
+          key={collection.id}
+          href={`/collections/${collection.handle}`}
+          onClick={close}
+          className={itemClasses}
+        >
+          {collection.title}
+        </Link>
+      ))}
+
+      {collections.length > 0 && (
+        <>
+          <div className="my-1 h-px bg-border" />
+          <Link
+            href="/collections"
+            onClick={close}
+            className={cn(itemClasses, 'text-muted-foreground')}
+          >
+            View all collections
+          </Link>
+        </>
+      )}
+    </>
+  );
+
+  const trigger = (
+    <button
+      onClick={toggle}
+      aria-expanded={open}
+      className={cn(
+        'flex items-center gap-x-1 text-foreground hover:text-muted-foreground transition-colors',
+        mobile && 'w-full justify-between'
+      )}
+    >
+      <span>{label}</span>
+      <RiArrowDownSLine
+        className={cn('size-4 transition-transform', open && 'rotate-180')}
+      />
+    </button>
+  );
+
+  if (mobile) {
+    return (
+      <div>
+        {trigger}
+        {open && (
+          <div className="mt-2 flex flex-col border-l border-border pl-1">
+            {body}
+          </div>
+        )}
+      </div>
+    );
+  }
+
+  return (
+    <div className="relative">
+      {trigger}
+
+      {open && (
+        <>
+          {/* Catches the click that dismisses the panel. */}
+          <div className="fixed inset-0 z-40" onClick={() => setOpen(false)} />
+          <div className="absolute left-0 top-full z-50 mt-2 max-h-[70vh] w-64 overflow-y-auto rounded-md border border-border bg-background py-1 shadow-md">
+            {body}
+          </div>
+        </>
+      )}
+    </div>
+  );
+};
+
+export default ShopMenu;